Regarding having to flip/change the record at inopportune times: Some players had a tall spindle in the middle that you could stack multiple records on; when one side ended, the next record in the stack came down. (Of course, this meant you could only listen to one side of each record without getting up and flipping the stack.) This is why some double-album sets used to be pressed with sides 1 and 4 on the same record, and 2 and 3 on the other one -- you stacked it so sides 1 and 2 would play without your having to get up, then you flipped the whole stack and played 3 and 4.

Also, you've ignored audio cassettes -- just about everyone in my age group (born 1973) or older had a cassette deck way before a CD player, and cassettes (especially mix tapes rather than storebought albums) can be pretty long on one side, even if you don't have one of those decks that automatically plays the other side when one side ends.